KR102691855B1 - Method of estimation the unbalance between battery cells through analysis of the cells equalization process and The Energy Management System using the same. - Google Patents

Abstract

One embodiment of the present invention provides an energy management system (EMS) that measures and monitors the state of charge of a plurality of battery cells, comprising: a cell equalization control circuit that performs cell equalization to reduce the deviation of the plurality of battery cells; a voltage deviation recurrence time measuring circuit that measures a voltage deviation recurrence time at which voltage imbalance of the plurality of battery cells occurs after cell equalization; and an alarm generation circuit that compares the voltage deviation recurrence time with a preset reference time to determine abnormal operation of the energy management system (EMS) and generate an alarm.

Description

Method of estimating the unbalance between battery cells through analysis of the cells equalization process and The Energy Management System using the same.

This embodiment relates to a method for estimating the imbalance between cells through analysis of the battery cell equalization process and an energy management system using the same. More specifically, the change in imbalance between cells is estimated by measuring the recurrence time of the voltage deviation between battery cells, and the cell equalization required. This relates to a method of estimating the imbalance between cells by analyzing time and power loss.

As the deviation between indicators such as voltage, state of charge (SOC), and state of health (SOH) between battery cells in a battery module increases, performance deterioration occurs.

It is relatively easy to measure parameters such as the output state (SOP: State of Power) and functional operating state (SOF) of a single battery cell, but in a battery module composed of multiple battery cells, the state of each battery cell is complex. Therefore, it becomes difficult to score a specific value - for example, 0 to 1 - or to derive a change rate or trend in the imbalance between cells due to changes over time.

Accordingly, technologies are emerging that reduce the imbalance between cells and the deviation of indicators in various ways using battery cell equalization technology. Since energy transfer technology between battery cells is complex, dissipative equalization can be easily applied in reality.

If additional information can be obtained during the cell equalization process, it is possible to improve inefficiency due to time or energy loss.

Against this background, the purpose of this embodiment is, in one aspect, a method for estimating changes in the imbalance between battery cells in a battery module by measuring the inter-cell voltage deviation (ΔV) regeneration time, which is a standard for performing battery cell equalization, and an energy management system using the same. is to provide. Applying the above method, the alarm indicator of the power management system (PMS) or energy management system (EMS) of an energy storage system (ESS) to determine the imbalance between battery cells and SOF degradation It can be used as.

Additionally, the purpose of this embodiment is to provide a method for estimating the imbalance between battery cells in a battery module by analyzing power loss and time required during the battery cell equalization process. By applying the above method, it can be used to estimate the internal resistance of battery cells and the imbalance change between battery cells can be derived.

In order to achieve the above-described object, the first embodiment is an energy management system (EMS) that measures and monitors the state of charge of a plurality of battery cells, and performs cell equalization to reduce the deviation of the plurality of battery cells. Cell equalization control circuit; a voltage deviation recurrence time measuring circuit that measures a voltage deviation recurrence time at which voltage imbalance of the plurality of battery cells occurs after cell equalization; and an alarm generation circuit that compares the voltage deviation recurrence time with a preset reference time to determine abnormal operation of the energy management system (EMS) and generate an alarm.

In an energy management system, the cell equalization control circuit can equalize the voltage of the same SOC (State of Charge) section of a plurality of battery cells connected in series.

In the energy management system, the voltage deviation recurrence time measurement circuit can measure the voltage deviation recurrence time at which the voltage deviation occurs based on the time when the voltage in the same SOC section is equalized.

In the energy management system, the voltage deviation recurrence time measurement circuit may calculate the voltage deviation by comparing the average voltage of the first group of battery cells with the average voltage of the second group of battery cells.

In the energy management system, the alarm generating circuit may generate a warning or replacement signal when the voltage deviation recurrence time exceeds the preset reference time.

The energy management system may further include a cell imbalance determination circuit that repeatedly obtains the voltage deviation recurrence period at different times and determines that a plurality of battery cells are in an imbalanced state when the voltage deviation recurrence period decreases. there is.

A cell equalization time analysis circuit that measures the time required for cell equalization in the energy management system from the first time point before the operation of the cell equalization control circuit to the second time point when the cell equalization operation of the cell equalization control circuit is completed. More may be included.

In the energy management system, the cell equalization time analysis circuit provides the same amount of current at different times and can measure the internal resistance of the battery cell by comparing the cell equalization time.

In order to achieve the above-mentioned purpose, the second embodiment is a method of estimating the imbalance between cells of an energy management system (EMS) that measures and monitors the state of charge of a plurality of battery cells, and determines the voltage deviation of the plurality of battery cells. discovering and performing cell equalization to reduce the voltage deviation; Measuring the voltage deviation recurrence time at which the voltage deviation of the battery cell reoccurs from the time the cell equalization is completed; and comparing the voltage deviation recurrence time with a preset reference time to determine abnormal operation of the energy management system and generate an alarm.

In the method of estimating the imbalance between cells of an energy management system (EMS), the cell equalization step may equalize the voltage of the same state of charge (SOC) section of a plurality of battery cells connected in series.

In the method of estimating the imbalance between cells of an energy management system (EMS), the step of measuring the voltage deviation recurrence time can calculate the voltage deviation by comparing the average voltage of the battery cells of the first group and the average voltage of the battery cells of the second group. .

In the method of estimating the imbalance between cells of an energy management system (EMS), the alarm generating step may generate a warning or replacement signal when the voltage deviation recurrence time exceeds the preset reference time.

In the inter-cell imbalance estimation method of the energy management system (EMS), the voltage deviation recurrence period at different times is repeatedly obtained, and when the voltage deviation recurrence period decreases, it is determined that a plurality of battery cells are in an imbalanced state. Additional steps may be included.

A method for estimating cell imbalance of an energy management system (EMS) may further include a cell equalization time measurement step of measuring the cell equalization time from a first point in time before the operation of the cell equalization control circuit to a second point in time when the cell equalization operation of the cell equalization control circuit is completed.

In the method of estimating the imbalance between cells of an energy management system (EMS), after measuring the time required for cell equalization, the same amount of current is provided at different times, and the internal resistance of the battery cell is measured by comparing the time required for cell equalization. Additional steps may be included.

As described above, according to this embodiment, additional information can be obtained during the battery cell equalization process, and inefficiency due to time or energy loss can be improved.

According to this embodiment, by providing a method for estimating changes in the imbalance between battery cells in a battery module by measuring the recurrence time of the inter-cell voltage deviation (ΔV), which is a standard for performing battery cell equalization, and an energy management system using the same, the imbalance between battery cells is also provided. And SOF degradation can be determined accurately.

According to this embodiment, by providing a method of estimating the imbalance between battery cells in a battery module by analyzing the power loss and time required during the battery cell equalization process, the internal resistance of the battery cell and the change in imbalance between battery cells can be accurately estimated.

1 is a diagram explaining the imbalance between battery cells.
Figure 2 is a diagram explaining the energy storage system according to this embodiment.
Figure 3 is a diagram explaining the equalization process between battery cells according to this embodiment.
Figure 4 is a flowchart explaining a method of determining an imbalance state between cells by measuring the recurrence time of the voltage deviation between cells according to this embodiment.
Figure 5 is a diagram explaining a method of measuring the inter-cell voltage deviation recurrence time according to this embodiment.
Figure 6 is a diagram explaining the alarm generation process according to this embodiment.
Figure 7 is a flowchart explaining a method of calculating the change in internal resistance based on measuring the time required for voltage equalization.
Figure 8 is a first example diagram illustrating a method for measuring cell equalization time required according to this embodiment.
Figure 9 is a second example diagram illustrating a method for measuring cell equalization time required according to this embodiment.

Hereinafter, some embodiments of the present invention will be described in detail through illustrative drawings. When adding reference numerals to components in each drawing, it should be noted that the same components are given the same reference numerals as much as possible even if they are shown in different drawings. Additionally, in describing the present invention, detailed descriptions of related known configurations or functions that are judged to be likely to obscure the gist of the present invention will be omitted.

Additionally, in describing the components of the present invention, terms such as first, second, a, and b may be used. These terms are only used to distinguish the component from other components, and the nature, order, or order of the component is not limited by the term. When a component is described as being “connected,” “coupled,” or “connected” to another component, that component may be directly connected or connected to that other component, but there is another component between each component. It will be understood that elements may be “connected,” “combined,” or “connected.”

1 is a diagram explaining the imbalance between battery cells.

Referring to FIG. 1, the imbalance between the batteries 10 and 20 can be confirmed by comparison.

In terms of energy, battery availability (SOF: State of Function) can be defined as the ratio of the available energy remaining in the battery and the maximum energy that can be stored in the battery. In particular, for batteries used in electric vehicles (EV), the remaining electric driving range is important. However, battery availability (SOF) is a long-term indicator, making it difficult to reflect the indicator and use it as a reference value for a short control/operation cycle (e.g., up to 1 Cycle).

In addition, in terms of power, battery availability (SOF) can be defined as (current power - required power) divided by (maximum power - required power) in terms of power. For batteries used in systems that require a specific power supply, the battery's availability (SOF) describes how the battery will meet the power demand.

In particular, predicting the state of charge (SOC) and state of health (SOH) is easy to apply to a specific cell, but is difficult to apply to a module in which two or more battery cells are connected serially within a battery module.

Since battery cells are greatly affected by other factors such as temperature and charge/discharge rate (C-rate), the objective standards for calculating battery availability (SOF) values according to state of charge (SOC) and state of health (SOH) are ambiguous. I do it.

At the battery module level, the minimum values of voltage, state of charge (SOC), state of health (SOH), and internal resistance of each cell connected in series within the battery module are constrained and determined.

For example, the capacity of a battery module can be defined as the correlation between battery capacity (C) and state of charge (SOC) as shown in (Equation 1).

(Equation 1)

The remaining usable capacity of the battery module can be defined as (Equation 2).

(Equation 2)

The state of charge (SOC) of the battery module can be defined as (Equation 3).

(Equation 3)

The smaller the imbalance (deviation) of the voltage, state of charge (SOC), and health status (SOH) indicators of each cell that makes up the battery module, the lower the availability/utilization rate of the battery module due to the imbalance (deviation) between cells can be improved. there is.

As shown in FIG. 1, the capacity of the first battery cell 10 may be composed of used capacity (C11), available capacity (C12), and waste capacity (C13), and the second battery cell 20 ) capacity can be composed of used capacity (C21), available capacity (C22), and waste capacity (C23).

If there is a deviation in the specific indicators of each cell that makes up the battery module - for example, voltage, state of charge (SOC), state of health (SOH), internal resistance - battery cell equalization is performed to resolve the imbalance of each battery cell. (Cell Equalization) procedure must be followed. If the deviation of the indicator of one or more battery cells is greater or less than a certain value, a battery cell equalization procedure is essential to prevent overcharge or overdischarge. Depending on the indicator of the battery cell, cell equalization such as state of charge (SOC) equalization, state of health (SOH) equalization, and remaining capacity (Remaining Capacity) equalization may be performed.

In addition, non-dissipative equalization is energy efficient, but it uses a capacitor and switch combined, a scattered DC/DC converter module, or a coaxial multi-winding transformer. Since energy must be transferred from a specific cell to another cell using a winding transformer, current redirector, independent charging, etc., it is complicated and difficult to use in practice.

Dissipative equalization is easier to implement than non-dissipative equalization methods, but some energy loss occurs and it must be performed at a low current, so the time required for equalization increases. In this case, if additional information - for example, the recurrence time of voltage deviation between cells, the power loss or time required during the cell equalization process - can be obtained during the equalization process, inefficiencies due to time or energy loss can be improved.

Figure 2 is a diagram explaining the energy storage system according to this embodiment.

Referring to FIG. 2, the energy storage system 100 may include a battery 110, a sensor 120, an energy management system 130, etc.

The battery 110 may be made of various types of secondary batteries, such as nickel-cadmium batteries, nickel-metal hydrogen batteries, lithium-ion batteries, all-solid-state batteries, and lead acid batteries.

The sensor 120 measures the state of the entire battery 110 module, such as temperature, voltage, and current, or measures the state of each cell of the battery 100 module, such as temperature, voltage, and current, and the related charge state. Information can be transmitted and received to the energy management system 130.

Energy management system (130) cell equalization control circuit (131), parameter calculation circuit (132), voltage deviation recurrence time measurement circuit (133), alarm generation circuit (134), cell equalization time analysis circuit (135), cell It may include an imbalance determination circuit 136, etc., and the charging state of a plurality of battery cells can be measured and monitored.

The cell equalization control circuit (131) can perform cell equalization to reduce the deviation of multiple battery cells.

The cell equalization control circuit 131 can equalize the voltage of the same state of charge (SOC) section of a plurality of battery cells connected in series.

The parameter calculation circuit 132 may calculate parameters according to different usage times in the same battery module based on the measured value of the sensor 120 or information stored in memory (not shown).

The voltage deviation recurrence time measurement circuit 133 can measure the voltage deviation recurrence time when voltage imbalance of a plurality of battery cells occurs after cell equalization.

The voltage deviation recurrence time measurement circuit 133 can measure the voltage deviation recurrence time from the time when the voltage of the same SOC section - for example, 90% SOC - is equalized to the point when the voltage deviation occurs.

The voltage deviation recurrence time measurement circuit 133 measures the average voltage of the battery cells of the first group - for example, the first to the fifth battery cells - and the batteries of the second group - for example, the sixth battery cell. The voltage deviation can be calculated by comparing the average voltage of the cell, but is not limited to this.

The alarm generating circuit 134 may generate a warning or replacement signal when the voltage deviation recurrence time exceeds the preset reference time. Additionally, the alarm generating circuit 134 may generate a warning or replacement signal when the change in voltage deviation (ΔV) is greater than the preset reference change amount (V_REF).

The cell imbalance determination circuit 136 repeatedly obtains the voltage deviation recurrence period at different times - for example, the 10th cycle and the 100th cycle - and when the voltage deviation recurrence period decreases, a plurality of battery cells become uneven. It can be judged as being in a state. For example, at the first point in time, the elapsed time for voltage deviation recurrence may be measured as 50 cycle service or 1000 km driving time, and at the second point in time, the elapsed time for voltage deviation recurrence may be measured as 25 cycle service or 500 km driving time. In this case, the degree of imbalance between battery cells, degree of module deterioration, and decrease in availability (SOF) can be determined by comparing the elapsed time of voltage deviation recurrence at the first and second times.

For example, if the average voltage of the first to fifth battery cells is 3.472V and the voltage of the sixth battery cell is 3.399V, the voltage of the first battery group is set to 3.472V, and the voltage of the second battery group is set to 3.472V. By setting it to 3.399V, the voltage deviation can be calculated as 0.073V. At this time, if the standard voltage deviation is 0.07V, it can be determined that an imbalance in the battery cell has occurred.

The cell equalization time analysis circuit 135 can measure the time required for cell equalization from the first time point before the operation of the cell equalization control circuit to the second time point when the cell equalization operation of the cell equalization control circuit is completed. .

The cell equalization time analysis circuit 135 provides the same amount of current at different times - for example, the 50th cycle time and the 500th cycle time - and provides the cell equalization time required - for example, 6 hours or 12 hours. You can measure the internal resistance of a battery cell by comparing time. To measure internal resistance, the correlation between the state of health (SOH) of the battery and internal resistance can be used.

For example, the state of health (SOH) of the battery can be defined as (Equation 4) below.

(Formula 4)

The cell equalization time required analysis circuit 135 is used in the same battery module for the same state of charge - for example, SOC 90% - at different usage points - for example, at the 50th cycle and at the 500th cycle. The time required for voltage equalization by flowing the same current can be compared with respect to the voltage deviation (ΔV) between cells.

For example, if the average voltage of the first to fifth battery cells is 3.472V and the voltage of the sixth battery cell is 3.399V, the voltage of the first battery group is set to 3.472V, and the voltage of the second battery group is set to 3.472V. By setting it to 3.399V, the voltage deviation can be calculated as 0.073V. At this time, the current may provide 0.55A, but is not limited thereto.

For the first to fifth battery cells, the time required for voltage equalization may be measured as 6 hours, and for the second time point, the time required for voltage equalization may be measured as 12 hours. In this case, the internal resistance of the first to fifth battery cells can be measured based on the time required for voltage equalization of the first to fifth battery cells.

Figure 3 is a diagram explaining the equalization process between battery cells according to this embodiment.

Referring to FIG. 3, the battery 110 uses a switch 112 to resolve the imbalance state of the plurality of battery cells 111-1, 111-2, 111-3, 111-4, 111-5, and 111-6. Dissipative equalization can be performed using -1, 112-2, 112-3, 112-4, 112-5, 112-6) and the resistor 113, but the shape and shape of the battery 110 The structure is not limited to this.

The energy management system 130 operates all of the switches 112-1, 112-2, 112-3, 112-4, 112-5, and 112-6 based on the operations and control signals of the circuits described above in FIG. 2. Alternatively, a portion may be opened or short-circuited, and the imbalance state of the plurality of battery cells 111-1, 111-2, 111-3, 111-4, 111-5, and 111-6 may be resolved.

Figure 4 is a flowchart explaining a method of determining an imbalance state between cells by measuring the recurrence time of the voltage deviation between cells according to this embodiment.

Referring to FIG. 4, the inter-cell imbalance estimation method 200 of an energy management system (EMS) that measures and monitors the state of charge of a plurality of battery cells includes a step in which battery cell imbalance occurs (S201), and battery cell equalization is performed. It may include a step (S202), a step of measuring the recurrence time of the voltage deviation between cells (S203), a step of determining the cell imbalance state (S204), and a step of generating an alarm of the energy storage device (S205).

The step in which an imbalance of battery cells occurs (S201) may be a step in which an imbalance in indicators such as voltage, SOC, SOH, and internal resistance of each battery cell occurs during the use of the battery module.

The battery cell equalization performing step (S202) may be a step of discovering index deviations of a plurality of battery cells and performing cell equalization to reduce the index deviations. For example, the indicator may be voltage, but is not limited thereto.

The battery cell equalization performing step (S202) may equalize the voltage of the same state of charge (SOC) section of a plurality of battery cells connected in series.

The step of measuring the inter-cell voltage deviation recurrence time (S203) may be a step of measuring the voltage deviation recurrence time of the battery cell from the time cell equalization is completed.

In the step of measuring the inter-cell voltage deviation recurrence time (S203), the voltage deviation may be calculated by comparing the average voltage of the first group of battery cells with the average voltage of the second group of battery cells. The energy management system can calculate the voltage deviation by comparing the voltage of individual battery cells rather than groups of battery cells.

The alarm generation step (S205) of the energy storage device may be a step of comparing the voltage deviation recurrence time with a preset reference time to determine abnormal operation of the energy management system and generate an alarm.

The alarm generation step (S205) of the energy storage device may generate a warning or replacement signal when the voltage deviation recurrence time exceeds a preset reference time.

The cell-to-cell imbalance estimation method 200 of an energy management system (EMS) that measures and monitors the state of charge of a plurality of battery cells repeatedly obtains the voltage deviation recurrence cycle at different points, and when the voltage deviation recurrence cycle decreases, may further include determining that the plurality of battery cells are in an uneven state (not shown).

Figure 5 is a diagram explaining a method of measuring the inter-cell voltage deviation recurrence time according to this embodiment.

Referring to FIG. 5, in the graph 200A immediately after equalization is performed, each battery cell may be maintained within a certain range. In the graph 200B after a certain period of time has passed after equalization, the voltage deviation of all or part of the battery cells may reoccur. In the graph 200B, a deviation may occur between the average voltage of the first group of first to fifth battery cells and the voltage of the second group of sixth battery cells. In this case, the energy management system (EMS) can determine whether the voltage deviation occurs again based on the voltage deviation of the first group and the second group.

Figure 6 is a diagram explaining the alarm generation process according to this embodiment.

Referring to FIG. 6, the operation of the system according to the elapsed time of recurrence of the voltage deviation of the battery cell can be checked in the comparison table 300.

For example, the elapsed time for recurrence of voltage deviation of a battery cell ( ) is the normal operation standard time ( ), it can be determined that the system operates normally without an alarm occurring.

For example, the elapsed time for recurrence of voltage deviation of a battery cell ( ) is the first warning standard time ( ) - for example, if the SOP is less than 40% - an alarm may be triggered.

For example, the elapsed time for recurrence of voltage deviation of a battery cell ( ) is the second warning standard time ( ) - for example, if the SOP is less than 40% - an alarm may be triggered.

For example, the elapsed time for recurrence of voltage deviation of a battery cell ( ) is the replacement standard time ( ), an alarm can be generated.

The battery management system measures the elapsed time for recurrence of voltage deviation of the battery cell ( ), the status of the battery module can be efficiently detected and controlled by sequentially setting the reference time and adjusting the strength of the warning.

Figure 6 is for illustrating the operation of the battery management system according to the elapsed time of recurrence of the voltage deviation of the battery cell, and the technical idea of the present invention is not limited thereto.

Figure 7 is a flowchart explaining a method of calculating the change in internal resistance based on measuring the time required for voltage equalization.

The inter-cell imbalance estimation method (400) of an energy management system (EMS) that measures and monitors the state of charge of a plurality of battery cells includes the steps of supplying the same current to the battery cells (S401), performing battery cell equalization (S402), It may include a voltage equalization time measurement step (S403) and an internal resistance change calculation step (S404).

The step of supplying the same current to the battery cells (S401) may be a step of supplying the same current to each battery cell in order to accurately measure the imbalance of the battery cell.

The battery cell equalization performing step (S402) may be a step of performing battery cell equalization to remove or reduce voltage deviation between cells for the same module.

The voltage equalization time measurement step (S403) may be a step of measuring the cell equalization time from a first time point before the battery cell equalization operation to a second time point when the cell equalization operation of the cell equalization control circuit is completed.

The internal resistance change calculation step (S404) may be a step of measuring the internal resistance of the battery cell by comparing the cell equalization time required after measuring the time required for cell equalization. Calculation of internal resistance changes can be performed on all or part of the battery cells, and can be performed by providing the same amount of current at different times.

Figure 8 is a first example diagram illustrating a method for measuring cell equalization time required according to this embodiment.

Figure 9 is a second example diagram illustrating a method for measuring cell equalization time required according to this embodiment.

Referring to FIGS. 8 and 9 , graphs 500A and 600A before cell equalization can be compared with graphs 500B and 600B immediately after cell equalization is completed.

Cell equalization performance time is defined as the time required to equalize voltage by flowing the same fixed current for the voltage deviation (ΔV) between cells at different usage points in the same battery module - for example, at the 50th cycle and at the 500th cycle. It can be.

There may be an embodiment in which the first to fifth battery cells are primarily equalized as shown in FIG. 8 and an embodiment in which the sixth battery cell is primarily equalized as shown in FIG. 9 .

The time at which the first to fifth battery cells are primarily equalized can be measured, and the internal resistance of the first to fifth battery cells can be calculated. Additionally, the time during which the sixth battery cell is primarily equalized can be measured, and the internal resistance of the sixth battery cell can be calculated. Based on this, the internal resistance of the first to fifth battery cells and the internal resistance of the sixth battery cell can be compared, and the internal resistance imbalance of the battery cells in the battery module can be determined.

The availability (SOF) of a battery module is calculated as the deviation of various factors such as voltage, state of charge (SOC), state of health (SOH), and internal resistance of each cell connected in series within the battery module, and the voltage is the actual measured value from the cell. However, since the state of charge (SOC), state of health (SOH), internal resistance, capacity, etc. are not actual measured values, the internal resistance of the battery cell is estimated based on the equalization time of the battery cell to ensure efficiency and accuracy of parameter calculation and verification. can be improved.

In other words, the result of equalization of the battery module can be used to additionally estimate the change in the degree of imbalance between batteries within the module due to aging (increasing number of cycles) of the battery. In addition, the results of the equalization performance of the battery module can be additionally obtained and utilized as internal resistance estimation information of the battery cell or module. Through this, it is possible to offset the time and energy wasted by equalization.

Claims (15)

In an energy management system (EMS) that measures and monitors the state of charge of a plurality of battery cells,
a cell equalization control circuit that performs cell equalization to reduce deviation of the plurality of battery cells;
a voltage deviation recurrence time measurement circuit that measures a voltage deviation recurrence time when voltage imbalance of the plurality of battery cells occurs after cell equalization;
an alarm generation circuit that determines abnormal operation of an energy management system (EMS) by comparing the voltage deviation recurrence time with a preset reference time and generates an alarm; and
A cell equalization time analysis circuit that measures the time required for cell equalization from a first time point before the operation of the cell equalization control circuit to a second time point when the cell equalization operation of the cell equalization control circuit is completed.
Including,
The cell equalization time analysis circuit provides the same amount of current at different times and measures the internal resistance of the battery cell by comparing the cell equalization time. According to claim 1,
The cell equalization control circuit is an energy management system that equalizes the voltage of the same SOC (State of Charge) section of a plurality of battery cells connected in series. According to claim 1,
The voltage deviation recurrence time measurement circuit is an energy management system that measures the voltage deviation recurrence time at which the voltage deviation occurs based on the time when the voltage in the same SOC section is equalized. According to claim 3,
The energy management system wherein the voltage deviation recurrence time measurement circuit calculates the voltage deviation by comparing the average voltage of the first group of battery cells with the average voltage of the second group of battery cells. According to claim 1,
The alarm generating circuit is an energy management system that generates a warning or replacement signal when the voltage deviation recurrence time exceeds the preset reference time. In an energy management system (EMS) that measures and monitors the state of charge of a plurality of battery cells,
a cell equalization control circuit that performs cell equalization to reduce deviation of the plurality of battery cells;
a voltage deviation recurrence time measuring circuit that measures a voltage deviation recurrence time at which voltage imbalance of the plurality of battery cells occurs after cell equalization;
an alarm generation circuit that determines abnormal operation of an energy management system (EMS) by comparing the voltage deviation recurrence time with a preset reference time and generates an alarm; and
An energy management system comprising a cell imbalance determination circuit that determines that a plurality of battery cells are in an imbalance state when the repeatedly obtained voltage deviation recurrence time decreases. delete delete In the method of estimating the imbalance between cells of an energy management system (EMS) that measures and monitors the state of charge of a plurality of battery cells,
discovering a voltage deviation of the plurality of battery cells and performing cell equalization to reduce the voltage deviation;
Measuring the voltage deviation recurrence time at which the voltage deviation of the battery cell reoccurs from the time the cell equalization is completed;
Comparing the voltage deviation recurrence time with a preset reference time to determine abnormal operation of the energy management system and generating an alarm;
A cell equalization time measurement step of measuring the time required for cell equalization from a first time point before the cell equalization operation to a second time point when the cell equalization operation is completed; and
After measuring the time required for cell equalization, providing current of the same magnitude at different times and comparing the time required for cell equalization to measure the internal resistance of the battery cell. According to clause 9,
The cell equalization performing step equalizes the voltage of the same SOC (State of Charge) section of a plurality of battery cells connected in series. According to clause 9,
In the step of measuring the voltage deviation recurrence time, the voltage deviation is calculated by comparing the average voltage of the first group of battery cells with the average voltage of the second group of battery cells. ◈Claim 12 was abandoned upon payment of the setup registration fee.◈ According to clause 9,
The alarm generation step generates a warning or replacement signal when the voltage deviation recurrence time exceeds the preset reference time. In the method of estimating the imbalance between cells of an energy management system (EMS) that measures and monitors the state of charge of a plurality of battery cells,
discovering a voltage deviation of the plurality of battery cells and performing cell equalization to reduce the voltage deviation;
Measuring the voltage deviation recurrence time at which the voltage deviation of the battery cell reoccurs from the time the cell equalization is completed;
Comparing the voltage deviation recurrence time with a preset reference time to determine abnormal operation of the energy management system and generating an alarm; and
A method comprising determining that a plurality of battery cells are in an uneven state when the repeatedly obtained voltage deviation recurrence time decreases.
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